1. Field of the Invention
This invention relates to a novel wind deflector that is adapted to mount directly on the rear window of a vehicle. The novel wind deflector provides a passive means for continuously removing liquid, snow and/or particulate material from the external surface of the rear window of a vehicle having an aerodynamic shape.
2. Description of the Prior Art
Wind deflectors are used to deflect air against the rear windows of moving vehicles that are not aerodynamically-shaped. Vehicles that are not aerodynamically-shaped, such as station wagons, vans, and the like, generally have square back ends or, at least, rear windows that are mounted at high angles with respect to the horizontal. The wind deflectors help to reduce the effects of eddy currents behind the vehicle when it is moving forward, thereby reducing the accumulation of dirt on the rear window. These prior wind deflectors are baffles that provide only a single deflecting surface. These wind deflectors cause considerable drag when the vehicle is traveling at high speeds, as described, for example, in U.S. Pat. Nos. 4,155,585 to J. A. Bott; 4,170,381 to F. A. Helm; 4,293,159 to J. A. Bott; 4,339,145 to J. A. Bott et al.
Motor vehicles with aerodynamic shapes do not have this problem. The aerodynamic shapes of such vehicles streamline the vehicles to avoid eddy currents and other forms of turbulence. But, because of the low angles of the rear windows relative to horizontal, aerodynamically-shaped vehicles have the problem of slow drainage of rain water from the exterior surface of the rear window. The problem is aggravated, because the aerodynamic shape of the vehicle causes rain water on the roof of the vehicle to stream over the rear window as the vehicle moves forward, instead of being blown from the trailing roof edge. Rain water or snow on the outer window surface distorts and/or obscures the driver's visibility through the rear window.
In some cases, the aerodynamically-shaped vehicle is equipped with rear window wipers to remove accumulated rain water more rapidly from the outer surface of the window. Such wipers are expensive to install and require maintenance during their operating lives. Also, rear window wipers are intermittent, not continuous, and frequently do not keep up with large amounts of rain water streaming over the window.